The LBTEK flat lens is a diffractive optical element that achieves beam convergence or divergence based on the polarization state of the incident light. The polarization handedness of the outgoing light is opposite to that of the incident light. By controlling the polarization state of the incident light, the energy distribution of the converging and diverging spots can be modulated. Therefore, compared to traditional lenses, the flat lens can function both as a converging lens and a diverging lens. The flat lens is a diffractive device with a planar structure, where the diffraction angle follows the relation sinθ = λ/p. Here, θ is the diffraction angle, λ is the design wavelength, and p is the radial period. The continuous variation of the periodic structure endows the flat lens with an aspherical aberration-free property. All rays passing through the effective aperture diffract at different radial periodic positions, ensuring that they converge precisely at the same point. The focal length of the flat lens primarily depends on its design wavelength, clear aperture, and diffraction period. LBTEK offers standard flat lenses with clear apertures of Ø20 mm, design wavelengths of 532 nm and 633 nm, and focal lengths of 50 mm, 75 mm, and 100 mm. In addition to standard flat lenses, LBTEK provides various customization services, including special substrates, dimensions, design wavelengths, focal lengths, and other specifications. For specific customization requirements, please contact LBTEK Technical Support.